Electrical probing is used to characterize the parametrics of components such as transistors, diodes, capacitors, and resistors
Electrical probing can be done while maintaining full electrical functionality of the parts or during the physical analysis. All electrical probing techniques use a variety of Semiconductor Parametric Analyzers (SPA) to collect and analyze the data. As a special form of probing, scanning capacitance microscopy (SCM) is used to create charge maps of electrically activated dopant implants.
Micro-probing is used for package trace analysis probing on functional parts and structures that are large enough to land micro-probes during physical analysis. For probing on functional parts, probe points are created on either side of the silicon. Backside probe points are used for flip chip products and are created through a process of die thinning, trench etching, and focused ion beam (FIB) editing. Front side probe points for wire-bond products are created in a similar process. Micro-probing is done on an airtable with the probe tips placed visually or with the aid of an optical microscope.
Nano-probing is used during physical analysis to measure components with small geometries, typically below the resolution of an optical microscope. The tool is used inside a focused ion beam (FIB) tool or a scanning electron microscope (SEM) that can resolve smaller features typically at the individual transistor level.
AFP resolves even the smallest features on today's IC devices. It uses atomic force microscopy (AFM) to identify probe landing areas and high resolution conductive probe tips.
SCM is an AFM mode that is used to map electrical carrier densities. A thin oxide layer is grown on the sample surface that acts as insulator between the AFM tip and the doped sample, thereby creating a capacitor. Upon scanning the AFM tip across the sample surface, a capacitance map is obtained.